RPi python script fails to run from: /etc/rc.local

I've tried to make this python script run from /etc/rc.local, crontab @reboot, and systemd via systemctl without any success.

The python script runs from the command line while logged in as user pi and exits gracefully into the background without issue. The same goes for running it at the prompt as user pi with: sh /etc/rc.local

Any guidance would be appreciated, as follows:

#!/usr/bin/python

#required libraries
    import sys
    import ssl
    import paho.mqtt.client as mqtt
    import json
    from pprint import pprint
    import Adafruit_CharLCD as LCD
    from textwrap import fill

#Configuration
    rootCAPath = "/home/pi/Cigar-Box/certs/rootCA.pem"
    certFilePath = "/home/pi/Cigar-Box/certs/xxxxxxxxxx-certificate.pem.crt"
    keyFilePath = "/home/pi/Cigar-Box/certs/xxxxxxxxxx-private.pem.key"
    iotThing = "Zorua"
    clientID = "Zorua"

#Device JSON initialization
    device = {'state': {'reported': {'HP':100} } }
    device['state']['reported']['color'] = {'r':0, 'g':0, 'b':0}

#Create LCD
    lcd = LCD.Adafruit_CharLCDPlate()

#LCD wrapper
    def set_lcd_color(R,G,B):
    global lcd
    device['state']['reported']['color']['r'] = R
    device['state']['reported']['color']['g'] = G
    device['state']['reported']['color']['b'] = B
    lcd.set_color(R, G, B)
    def set_lcd_message(message):
    global lcd
    device['state']['reported']['msg'] = message
    lcd.clear()

#Word wrap to fit 16-char wide display and add capitalization
    lcd_message = fill(message.capitalize(),16)
    lcd.message(lcd_message)

# Initialize the LCD using the pins
    set_lcd_message('Initializing...')
    set_lcd_color(0, 0, 1)

#called while client tries to establish connection with the server
    def on_connect(mqttc, obj, flags, rc):
    print "Connecting..."
    if rc==0:
    print ("Subscriber Connection status code: "+str(rc)+" | Connectionstatus: successful")

#We only want to be notified about things we need to change to stay in sync with AWS
    mqttc.subscribe("$aws/things/" + iotThing + "/shadow/update/delta", qos=1)
    elif rc==1:
    print ("Subscriber Connection status code: "+str(rc)+" | Connection status: Connection refused")
    print ("Subscriber Connection status code: "+str(rc))

#called when a topic is successfully subscribed to
    def on_subscribe(mqttc, obj, mid, granted_qos):
    print("Subscribed: "+str(mid)+" "+str(granted_qos)+"data"+str(obj))
    set_lcd_color(0,1,0)
    set_lcd_message('Connected!\nReady for input')

#Let AWS know about the current state of the plate so we can tell us what's     out of sync
    mqttc.publish("$aws/things/" + iotThing + "/shadow/update", json.dumps(device))

#called when a message is received by a topic
#Messages are formatted in JSON
#When working with /update, we might not find all keys all the time, so we need to handle that
    def on_message(mqttc, obj, msg):
    try:
    data = json.loads(msg.payload)
    update = data['state']
    except:
    return

#Look for a message in the update. If it's there, we need to update the display
    if 'msg' in update.keys():
    try:
    set_lcd_message(update['msg'])
    except:
    print("Could not enact message from topic: "+msg.topic+" | QoS: "+str(msg.qos)+" | Data Received: "+str(msg.payload))

#Look to see if the status of R, G, or B has changed for the display
    if 'color' in update.keys():
    try: lcd_r = update['color']['r']
    except: lcd_r = device['state']['reported']['color']['r']
    try: lcd_g = update['color']['g']
    except: lcd_g = device['state']['reported']['color']['g']
    try: lcd_b = update['color']['b']
    except: lcd_b = device['state']['reported']['color']['b']
    set_lcd_color(lcd_r,
                  lcd_g,
                  lcd_b)
#Let AWS know we've updated the display
    mqttc.publish("$aws/things/Zorua/shadow/update", json.dumps(device))

#creating a client with client-id=Zorua
    mqttc = mqtt.Client(client_id=clientID)
    mqttc.on_connect = on_connect
    mqttc.on_reconnect = on_connect
    mqttc.on_subscribe = on_subscribe
    mqttc.on_message = on_message

#Configure network encryption and authentication options. Enables SSL/TLS support.
#adding client-side certificates and enabling tlsv1.2 support as required by aws-iot service
    mqttc.tls_set(rootCAPath,
    certfile=certFilePath,
    keyfile=keyFilePath,
    tls_version=ssl.PROTOCOL_TLSv1_2, ciphers=None)

#connecting to aws-account-specific-iot-endpoint
    print ("About to connect")
    mqttc.connect("lettersandnumbers.iot.us-west-2.amazonaws.com", port=8883) #AWS IoT service hostname and portno

#automatically handles reconnecting
    mqttc.loop_forever()

The code located in /etc/rc.local followed by a simple redirect test to see if rc.local is behaving

# Default code located inside /etc/rc.local
# Print the IP address

    _IP=$(hostname -I) || true
    if [ "$_IP" ]; then
    printf "My IP address is %s\n" "$_IP" > /home/pi/cigarbox.log
    fi
    exit 0

######################################################################


# After rebooting RPi = no output to log
    pi@cigarbox:~ $ cat cigarbox.log

# Running /etc/rc.local from the command line
    pi@cigarbox:~ $ sh /etc/rc.local

# After running /etc/rc.local locally = output to log
    pi@cigarbox:~ $ cat cigarbox.log
    My IP address is 192.168.0.21

Here are the paths for pi and root

# Running as pi        
    pi@cigarbox:~ $ echo $PATH
    /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/games:/usr/games

# Running s root 
    pi@cigarbox:~ $ su - root
    Password:
    root@cigarbox:~# echo $PATH
    /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

Nice. It looks like rc.local is behaving

     # Cat and pipe of boot.log
     root@cigarbox:~# cat /var/log/boot.log | grep rc.local
     Starting /etc/rc.local Compatibility...
     [  OK  ] Started /etc/rc.local Compatibility.

However, I've tried this in the past. See line commented out below the python command and path in parenthesis, per suggestion. So, the script still won't run out of /etc/rc.local

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
#_IP=$(hostname -I) || true
#if [ "$_IP" ]; then
#  printf "My IP address is %s\n" "$_IP" > /home/pi/cigarbox.log
#fi

    (python /home/pi/Cigar-Box/CigarBox.py)&

#/usr/bin/python /home/pi/Cigar-Box/CigarBox.py > /home/pi/cigarbox.log 2>&1 &

    exit 0

Hmm, it appears that I need 10 good boy points to upload images. I'll have to post the successful completion of this group's most appreciated help. Thank you all..photo URL and solution to follow.

Okay, here's a link to a photo of my voice recognition project that now starts automatically because of the support from my new friends at stackoverflow:

https://drive.google.com/file/d/19ribELmAnQFy4jfzi5D6I7fk91naS8J7/view?usp=drivesdk

To run python script via `/etc/rc.local`:

1) Edit the file using sudo /etc/rc.local;

2) Add the following to the file right before exit 0:

(sleep 10;python /home/pi/Cigar-Box/CigarBox.py)&

The parentheses allows your to run multiple commands in the background. The sleep 10 will delay the running of script by 10 seconds, as some of the services that your script depend on may not be available yet at the time of booting rc.local.

Alternatively you can use crontab @reboot to automate the execution of your script.

Using crontab:

1) run command line sudo crontab -e;

2) add the command to the end of the file:

@reboot /usr/bin/python /home/pi/Cigar-Box/CigarBox.py